Homocysteine

Homocysteine is an amino acid that your body uses to make proteins. Normally, vitamin B12, B6, and folic acid (also called folate or vitamin B9) quickly break down homocysteine and change it into other substances your body needs. High levels of homocysteine in your blood may indicate that this process isn’t working properly or that you lack certain B vitamins. This test can suggest vitamin B6, B12, and folic acid deficiency, or assess risk factors for heart disease and stroke.